A Curated List of Falsehoods Programmers Believe In
github.com
github.com
I don't think these kinds of lists are necessarily always true, or always relevant, but I think they are great at provoking thought, and great at reminding us that real life is impossible to cleanly codify into a computer model.
Also see Joe Armstrong's talk, The Mess We Are In: https://www.youtube.com/watch?v=lKXe3HUG2l4
(The exception being, of course, building something for the sake of learning. By all means, build your own date formatting functions, but don't put them in production.)
As a completely unrelated aside, I wonder if there should be a "Falsehoods programmers believe about libraries"
"This bug must come from backend" "This bug must come from frontend"